Optical Article Comprising a Substrate with Embedded Particles for Abrasion and/or Scratch Resistance Enchancement

Abstract

The invention relates to an optical article having a substrate made of an optical material comprising a polymer matrix and an improved abrasion and/or scratch resistance. The substrate comprises an external layer in which particles functionalized by a silane coupling agent are embedded into the polymer matrix, the Bayer value of said substrate determined in accordance with the ASTM F735-81 standard being at least 30% greater than the Bayer value of the same substrate with no embedded particles.

1 .- 15 . (canceled) 
     
     
         16 . An optical article having a substrate made of an optical material comprising a polymer matrix, wherein the substrate comprises an external layer in which particles are embedded into the polymer matrix, a Bayer value of said substrate determined in accordance with the ASTM F735-81 standard being at least 30% greater than a Bayer value of the same substrate with no embedded particles, and the particles are functionalized with a silane coupling agent. 
     
     
         17 . The optical article of  claim 16 , wherein the silane coupling agent is chosen from epoxysilanes, aminosilanes and unsaturated silanes. 
     
     
         18 . The optical article of  claim 16 , wherein a refractive index of the particles (R p ) is lower than a refractive index of the polymer matrix (%). 
     
     
         19 . The optical article of  claim 18 , wherein R p −0.1<R s . 
     
     
         20 . The optical article of  claim 19 , wherein R p −0.05<R s . 
     
     
         21 . The optical article of  claim 16 , wherein the particles are metal oxide, metal hydroxide or metal fluoride particles. 
     
     
         22 . The optical article of  claim 21 , wherein the particles are chosen from SiO 2 , MgF 2 , ZrO 2 , and TiO 2  particles. 
     
     
         23 . The optical article of  claim 16 , wherein an additive is contained in the particles or grafted to the particles. 
     
     
         24 . The optical article of  claim 23 , wherein the additive is a light-absorbing additive. 
     
     
         25 . The optical article of  claim 16 , wherein the external layer of the substrate in which the particles are embedded has a thickness lower than or equal to 1 μm. 
     
     
         26 . The optical article of  claim 16 , wherein the particles have a diameter of less than 150 nm. 
     
     
         27 . The optical article of  claim 16 , wherein the silane coupling agent is an unsaturated silane chosen from vinylsilanes, allylsilanes, acrylic silanes and methacrylic silanes. 
     
     
         28 . A process for making the optical article of  claim 16 , comprising:
 (a) providing a mold having an inner face;   (b) covering at least one portion of said inner face of the mold by particles;   (c) filling the mold with a polymerizable composition;   (d) curing said polymerizable composition; and   (e) obtaining an optical article having a substrate made of an optical material comprising a polymer matrix, wherein the substrate comprises an external layer in which particles are embedded into the polymer matrix;   
       wherein the Bayer value of said substrate determined in accordance with the ASTM F735-81 standard is at least 30% greater than the Bayer value of the same substrate with no embedded particles. 
     
     
         29 . The process of  claim 28 , wherein in (b), the particles are colloidal particles. 
     
     
         30 . The process of  claim 28 , wherein a refractive index of the particles (R p ) is lower than a refractive index of the polymer matrix (R s ). 
     
     
         31 . The process of  claim 30 , wherein R p −0.1<R s . 
     
     
         32 . The process of  claim 31 , wherein R p −0.05<R s . 
     
     
         33 . The process of  claim 32 , wherein R p +0.25<R s . 
     
     
         34 . The process of  claim 28 , comprising a step of capping the mold inner face with at least one capping agent before step (b). 
     
     
         35 . A process for increasing the abrasion- and/or scratch-resistance of an optical article, the optical article having a substrate made of an optical material comprising a polymer matrix, comprising embedding particles into the polymer matrix in an external layer of the substrate, wherein a Bayer value of said substrate determined in accordance with the ASTM F735-81 standard is at least 30% greater than a Bayer value of the same substrate with no embedded particles.